Advice on an electric lawnmower

[Zambam]

I've been using a corded electric lawnmower for our house for more than 8 years, before that was a gas mower. Works great, no gasoline to deal with! But the part I dislike the most is the cord, which takes time to setup and care to not cut the cord. Running 100 ft out to the sidewalk strip of grass is the part I hate most. Our house is on a 60' x 100' lot, approx 1/3 of that is lawn, the rest is house, paved driveway and garage.

What size battery (in voltage and AH) do I need in a cordless to get the job done? I see they go from 24V to 80V, AH from 4 to 6. Don't want to spend a lot of money since the old corded mower was replaced with a new one just last year. I can still use the corded to do some of the cutting and the cordless for the parts further out.

 

[spinningmagnets]

The EGO 56V is pricey, but I have one and I like it a lot.

 

[Zambam]

This one? https://www.lowes.com/pd/EGO-Power-...4PrD_nouRi9Pg5WucvxoC0F8QAvD_BwE&gclsrc=aw.ds

or this with 2 batteries?

EGO Power+ 21 in. 56V Lawn Mower Kit (2 Batteries & Charger) - Ace Hardware

The EGO Power+ 21 in. Lawn Mower delivers long-lasting battery power, rapid charging and durability in all-weather conditions. Find it at Ace Hardware.

www.acehardware.com

Any other suggestion?

 

[pwd]

I found a nice used 48V lawnmower that was designed to work on lead acid. I think the lead acid was 10ah bricks. I am now using it on an old 52V 15ah Samsung 30Q ebike pack. I have a similar sized lot; maybe a bit less grass. I'd estimate I use anywhere from 25%-40% of its capacity when doing the full yard; depending on the grass conditions etc... So I'd say around 155 to 305 watt hours.... more capacity is always better if you can fit and afford it.

 

[Zambam]

I found a nice used 48V lawnmower that was designed to work on lead acid. I think the lead acid was 10ah bricks. I am now using it on an old 52V 15ah Samsung 30Q ebike pack. I have a similar sized lot; maybe a bit less grass. I'd estimate I use anywhere from 25%-40% of its capacity when doing the full yard; depending on the grass conditions etc... So I'd say around 155 to 305 watt hours.... more capacity is always better if you can fit and afford it.

What did you pay for a used mower? I looked on Offerup locally and there was only 2 new ones listed.

Anyone with experience with Greenworks? This one is 21" 40V with 4AH battery included on sale for $380

40V 21-Inch Cordless Lawn Mower | Greenworks

Mow the toughest yards with 2x more torque! Deck Size: 21” What's Included: One (1) 4.0Ah USB Battery + One (1) 2.0Ah USB Battery and Charger Power 75+ Tools with any Greenworks 40V Battery(*40V 8Ah battery can't fit with this mower) Acreage: Up to 1/3 Acre

www.greenworkstools.com

 

[Zambam]

Further looking led me to this Greenworks 21" 60V 5AH push for $370 total shipped (w discount code). It has a brushless motor. Is that good in a lawn mower?

60V 21-Inch Cordless Lawn Mower | Greenworks Pro

The Greenworks Pro 60V Brushless Lawn Mower provides the power you need with up to 60 minutes of run time on a fully charged 5.0 Ah battery. Shop now!

www.greenworkstools.com

 

[Comrade]

They are weaker. I've never used a corded one. How many watts does that consume? I'd guess the typical cordless push mower is somewhere in the 300W range. They have trouble with taller grass. You might need to cut more often or do it in 2 passes with cordless.

 

[gromike]

I have a 5 year-old 40v Greenworks mower. It works great. A couple of 4 amp-hour batteries and I'm good to mow.

 

[Zambam]

They are weaker. I've never used a corded one. How many watts does that consume? I'd guess the typical cordless push mower is somewhere in the 300W range. They have trouble with taller grass. You might need to cut more often or do it in 2 passes with cordless.

Brushless motors are weaker then brushed?

 

[amberwolf]

The motor itself may not be, but because it must be run by a controller that must by nature limit the current available from the battery, a brushless system is usually lower initial loaded torque than a brushed. The brushed ones have no controller, only current limit is whatever fuse is in the system and the diode or rectifier if it is a PM (vs universal) brushed motor.

The brushless is more energy efficient, if designed well.

You can also convert to cordless....

Cordless conversion for Black & Decker MM850 Mower

This one was relatively easy, though Jelly is a bit critical: It's a brushed permanent magnet motor, so it works just as well on DC as AC. (it even uses a large full-wave bridge rectifier between the switch and the motor...I didn't bypass that solely because I left this whole thing setup so...

endless-sphere.com

It looks much neater now (the pics there were the initial testing phase), but it still works. The only fault so far was blowing up the rectifier (which wasnt' needed with battery operation anyway) when a piece of stick got sucked in and jammed the blade hard before I could let go of the handle, and POOF. Bypassed that and back in business.

 

[Zambam]

Cool conversion! Not something I can do without resources needed. I placed an order on a Greenworks 60V brushless MODEL# MO60L516.

Pertinent details from their ad:

2x more torque takes the work out of yard work
Powerfully smart. Tackle the toughest yards, one-handed—because our smart mowers never bog down. When grass gets thick, tall, or wet, Greenworks sensors tell our TRUBRUSHLESSTM motor to rush power to the mower blades. The end result? The perfect lawn, every time.

 

[Zambam]

I have a 5 year-old 40v Greenworks mower. It works great. A couple of 4 amp-hour batteries and I'm good to mow.

Nice! Is yours brushless or brushed?

 

[99t4]

OP I see you have ordered your preferred cordless mower, and plan on possibly using your corded as well.
Since you mentioned the worst aspect of the corded mower for you is dealing with the cord, I suggest this cord winder. If it can fit in your application, it may ease the hassles of cord wrangling for you:

https://www.amazon.com/Green-Leaf-WW3D-Wonder-Extension/dp/B07CV4L6HX/ref=d_m_crc_dp_lf_d_t1_vft_med_sccl_2_3/142-4510721-0582102

 

[Zambam]

The EGO 56V is pricey, but I have one and I like it a lot.

Is your's brushless or brushed? Ego makes both in 56V.

 

[Zambam]

OP I see you have ordered your preferred cordless mower, and plan on possibly using your corded as well.
Since you mentioned the worst aspect of the corded mower for you is dealing with the cord, I suggest this cord winder. If it can fit in your application, it may ease the hassles of cord wrangling for you:

https://www.amazon.com/Green-Leaf-WW3D-Wonder-Extension/dp/B07CV4L6HX/ref=d_m_crc_dp_lf_d_t1_vft_med_sccl_2_3/142-4510721-0582102

Hey, that looks like a great cord winder! Thanks for the heads-up. Unfortunately I don't think it will work for me since my 100 plus ft extension cord consist of 3 pieces plugged into each other. First is a 20' 8 gauge section at the outlet, then a 50' 10 gauge section, then a 50' 12 gauge section to the mower. Plug connections are held together with bicycle inner tube so they don't get pulled apart while mowing.

Just got an email that my Greenworks 60V brushless mower will be delivered today by Fedex. Pretty amazing free next day delivery!

 

[pwd]

What did you pay for a used mower? I looked on Offerup locally and there was only 2 new ones listed.

I think I payed around $30; the mower didn't work because half of the lead acid bricks were dead.

 

[Zambam]

Lawnmower was delivered late today, not yesterday. I am a little pissed and feel deceived! It's advertised as a 60V mower but the manual for the battery says 54 V 5AH 270Wh 60V Max. The charger is 60V, not the battery! Would you call that false advertising? Should I file a complaint?

 

[lnanek]

Lithium battery specs often use 3.6V per cell in series as the voltage rating. You can charge them to 4.2V per cell, but you wouldn't want your electronics to stop working as soon as the cells drop to 4.1V. I don't know about Greenworks, but Dewalt 60V packs are 15 cells:

DeWalt 60V

I originally thought that the DeWalt 60V packs must be 14S (fully-charged 14S packs are 58.8V). However, a teardown video showed that they are definitely 15S. A nominal 3.6V per cell would be 3.6V X 15S = 54.0V, and fully-charged they are 4.2V X 15S = 63.0V

Using cordless tool batteries for an ebike

If…the idea of using cordless tool batteries to power an ebike has ever crossed your mind? You are not alone. After some research, I found out that…it is not as crazy as it might sound.…

www.electricbike.com

So you can see how that could be called both a 54V battery or a 60V battery depending on the voltage per cell used for calculation.

 

[amberwolf]

FWIW, power tools usually use something around full charge voltage as the marketing voltage, unlike ebikes/etc that use the average pack voltage; AFAICR they've been doing that since at least the NiCd days. There's a number of threads about power tool packs and such that discuss the history of this over the years if you're interested.

At least they're not actually advertising falsely, just differently, unlike the many "powerpack" and "lithium jump start" batteries and devices out there that add all the Ah of all the cells IN SERIES together as the capacity, which is a flat out lie, since you can only add capacities in parallel. Some of them do it even worse and use Wh instead, with max charge voltage of all cells added together, even if they are in parallel (voltages add only in series), and then multiply that by the max possible capacity of every cell (series and parallel), which makes a complete lie out of their rating.

 

[Zambam]

Lithium battery specs often use 3.6V per cell in series as the voltage rating. You can charge them to 4.2V per cell, but you wouldn't want your electronics to stop working as soon as the cells drop to 4.1V. I don't know about Greenworks, but Dewalt 60V packs are 15 cells:

Using cordless tool batteries for an ebike

If…the idea of using cordless tool batteries to power an ebike has ever crossed your mind? You are not alone. After some research, I found out that…it is not as crazy as it might sound.…

www.electricbike.com

So you can see how that could be called both a 54V battery or a 60V battery depending on the voltage per cell used for calculation.

Thanks for that article. My battery arrived measuring 53.3V before I put it on the charger, that's why I was concerned. Per the KillaWatt, the charger drew a max of 372 watts and consumed 0.21 kwh in 36 min when the charger LED turned solid green (still drawing 195w, has not turn itself off yet) when I removed the battery and measured it at 61.5V.

Mowed the lawn today. It performed well with dry grass at 6" -7", did not bog down at all and sounded like it ran at a constant RPM. I feel it has more power and torque and did a better job than our 2 corded mowers. Unfortunately I forgot to time how long it ran (will try to remember to do that next time). When I finished, it had 1 LED left out of 4 on the battery indicator.

Only thing I don't like is the weight. It's heavy! Pushing and maneuvering takes more effort. I was not able to find the weight of this mower on their ad. before buying. The box it was shipped in says 65 lb with battery, which is much heavier than our Ryobi 20" corded mower at 40 lbs and the previous Greenworks corded 21" at 53 lbs.

I charged the battery after mowing and let the charger run till it shut itself off. There's a fan in the charger which blows air up and through the battery which has vents all over. Battery went from 56V to 62.4V and consumed 0.14 kwh. Shouldn't it go to 63V at full charge?

 

[Zambam]

FWIW, power tools usually use something around full charge voltage as the marketing voltage, unlike ebikes/etc that use the average pack voltage; AFAICR they've been doing that since at least the NiCd days. There's a number of threads about power tool packs and such that discuss the history of this over the years if you're interested.

At least they're not actually advertising falsely, just differently, unlike the many "powerpack" and "lithium jump start" batteries and devices out there that add all the Ah of all the cells IN SERIES together as the capacity, which is a flat out lie, since you can only add capacities in parallel. Some of them do it even worse and use Wh instead, with max charge voltage of all cells added together, even if they are in parallel (voltages add only in series), and then multiply that by the max possible capacity of every cell (series and parallel), which makes a complete lie out of their rating.

I thought power tool batteries use the same convention as ebikes. Now I know they do not. Thanks! I've never owned a jump start power pack. Thanks for the warning (if I ever buy one).

 

[nicobie]

EGO makes quality stuff and there is nothing wrong with brushless motors. In the long run they are way better than brushed.

Now that you have the battery you can buy other Ego tools cheap when only buying the bare tool. I bought a bare tool only blower and hedge clipper dirt cheap on ebay.

 

[amberwolf]

there is nothing wrong with brushless motors. In the long run they are way better than brushed.

Yes--it is not the motor, but the controller, that usually makes them a less torquey option than a brushed motor. If they used a big enough controller, the brushless would be just as "good" for the things that require that.